As is known, these articles are obtained by laying a sheet of impermeable material over a sheet of permeable material (of non-woven fabric), with a padding consisting of an absorbent pad interposed between the two sheets. More specifically, both in the case of nappies of children and in the case of nappies for adults, it is usual to add accessory components such as lateral flaps for closing the nappy round the wearer's waist.
Generally speaking, in the prior art machines, the lateral closure flaps are applied along certain stretches of a continuous web of a material for making nappies, these stretches corresponding to the single nappies, when subsequently divided.
These machines comprise a conveyor for feeding a continuous strip of elastomeric material, a device for cutting a continuous strip of elastomeric material into suitably shaped single pieces constituting the lateral flaps for closing the nappies, and a unit for forming and applying pairs of lateral flaps to the continuous band.
The cutting device makes a succession of pieces forming the above-mentioned lateral flaps which are fed by a conveyor roller to the unit for forming and applying the pairs of lateral flaps.
More in detail, each pair of lateral flaps is defined by a first and a second piece, and the cutting device makes a continuous and alternating succession of first and second pieces.
Between the conveyor roller and the forming and applying unit, the machine has a pair of spacer rollers, which are able to pick up respective pieces from the continuous succession fed by the conveyor roller.
A first spacer roller picks up from the succession only the first piece, whilst the second picks up only the second pieces.
The first and the second roller feed the respective pieces to the forming and applying unit, which makes the respective pairs of first and second pieces, which are mutually aligned and spaced by a predetermined length on the basis of the transversal dimensions of the continuous band of a material for making nappies. The forming and applying unit then applies in step each pair on the continuous band.
More specifically, it is known how, with the variation in the type of absorbent article to be made, the dimensions and the format of the lateral flaps also vary.
It is therefore necessary to replace one or more devices of the machine with others suitable to operate according to the new format of the absorbent article and the lateral flaps to be applied.
The new devices generally have new and different structural and functional characteristics and, therefore, problems occur linked to the operational or structural incompatibility between the new devices and those replaced.
To overcome this problem, further additional devices are used which act between the various devices replaced and those not replaced, resulting, however, in a further increase in the structural and functional complexity of the machine and the costs for making and preparing the machine for the new format to be made.